class_docstr: Test upgrade_opt behavior.
code: def setUpClass(cls):
      if cls is _AbstractTRATest:
          raise unittest.SkipTest("Skip abstract parent class")
      super(_AbstractTRATest, cls).setUpClass()
  
imports: import os
  import pytest
  import unittest
  import parlai.utils.testing
  from parlai.tasks.integration_tests.agents import CandidateTeacher
label_desc: Use image node_id 1 for calling the _AbstractTRATest obj's underlying member method code with example usage: obj.setUpClass(cls) without return types